Microflask heating device



Feb. 25, 1969 H. M OREY MICROFLASK HEATING DEVICE Filed Nov. 1 0, 1965 IINVENTOR. GLEN H. MORY United States Patent 2 Claims ABSTRACT OF THE DISCLOSURE A heating device for microflasks includes a metallic well member seated in an aperture in the refractory top wall of a cup-like body member. An electric heating element comprising wires encased in refractory textile tubes with high temperature insulation therein is wound around the exterior of the well member together with a refractory cord which spaces the adjacent element convolutions and holds the element in place. The upper end of the well is flared outwardly to form a seat on which the bottom of a flask can rest. The well member is surrounded by thermal insulation material contained in the body member.

This invention relates to heating devices and is particularly concerned with an electrically operated heating device particularly adapted for use with small flasks known as microflasks.

Flasks of the nature referred to range in size from extremely small flasks up to about 50 cc. capacity. Several different sizes are available such as cc., 20 cc., 25 cc., etc. up to about 50 cc. capacity as a maximum. The flasks vary in shape, sometimes being spherical and sometimes being conical in shape.

Such flasks are employed for the purpose of treating extremely small quantities of fluid, for example, by distillation. Since the quantities being treated are extremely small it becomes important to distill or treat the contents down to the very last drop.

The heating of such flasks properly has heretofore been rather diflicult because the sides of such a small flask above the bottom can readily be heated to too high a temperature in heating the flask so as to distill therefrom the last bit of fluid therein.

It has been known to heat such flasks by flexible mantles in which the flask is placed and which mantles are electrically heated. This however results in the super-heating of the portion of the flask wall above the liquid level and is thus not a desirable arrangement nor is it economical of heat. Furthermore, since the flasks vary widely in size and shape a great many different types of heating mantles are required to provide an adequate range thereof to heat all known flasks. Furthermore, flasks of a different shape may be produced at any time, either through request or because of some change in the manufacturing process and it might be that under these circumstances the existing heating mantles would not fit the flasks very well and new mantles be required which would, of course be expensive.

The present invention proposes to provide a heating device for microflasks in which all of the heat supplied to the flask is directed to a small region at the extreme bottom of the flask thereby avoiding overheating of the sides of the flask and permitting distillation of minute quantities of liquid.

With the foregoing in mind it is the object of the present invention to provide a method and apparatus particularly adapted for the heating of microflasks in which the difficulties referred to above are eliminated.

Another object of this invention is the provision of a 3,430,032 Patented Feb. 25, 1969 method and apparatus for heating microflask in which one and the same heater can be employed for heating any type or shape of microflask.

Still another object of this invention is the provision of a method and apparatus for heating microflasks in which substantially a point source of heat is applied to the very bottom of the flask thereby eliminating overheating of the bare sidewalls of the flask and obtaining distillation of the contents of the flask down to the very last drop.

These and other objects and advantages of the present invention will become more apparent upon reference to the following specification taken in connection with the accompanying drawing, in which:

FIGURE 1 is a perspective View showing a setup that might be made wherein a microflask is being heated by a heating device according to the present invention;

FIGURE 2 is a vertical sectional view indicated by line II-II on FIGURE 1 showing more in detail the construction of the heating device according to the present invention; and

FIGURE 3 is an enlarged fragmentary view showing a portion of the heating well and the heating element thereof.

Referring to the drawing somewhat more in detail, a heating device according to the present invention is indi cated generally at 10 and the microflask being heated thereby is indicated at 12. A support of any suitable type as indicated at 14 is employed for supporting the microflask above and resting on the heating device. The heating device of the present invention, on the other hand, has a threaded boss 16 on one side into which extends a threaded rod 18 that is connected with a clamp 20 at its outer end. Clamp 20 may be adjustable along a vertical post 22 of a support which includes a base 24. The support 14 from the microflask similarly is connected in any suitable manner with post 22. Clamp 20 pertaining to the heating device permits it to be moved vertically to accommodate the setup to different types of flasks quite readily. Either of the supports could, of course, be movable, or separate supporting means could be provided for each of the heating device and the microflask.

Referring now to FIGURE 2 it will be seen that the heating device comprises a cylindrical outer metal frame to one side of which is connected the aforementioned threaded boss 16 that receives the threaded end of support rod 18. Cylindrical frame 30 is closed at the bottom by cap 32 held in place as by screw means 34. At the top cylindrical frame 30 has its upper edge fitted in an annular groove in a block of insulating material 36 which may, for example, be hard asbestos or the like.

Member 36 has a central bore therein and extending through the central bore is a metal well 38 that extends down into the body of the heating device a substantial distance. The top of the well is flared out at 39 While the bottom of well 38 is preferably closed as by a disc 40 Welded thereto. Wound about the well is a heating element 42, the individual wires being encased, for example, in asbestos or quartz (refractory) textile tubes with high temperature insulation therein. The terminal wires leading from the heating element, indicated at 44, lead to a fitting 46 on one side of the device to which electrical connection can be made by a suitable electric cord.

The inside of the body of the heater is packed with insulating material 48 which may, for example, be in the form of asbestos Wool or the like.

In operation, when the resistance heating element 42 is energized the well 38 will become hot and most of the heat developed by the resistance heating element will be extracted from the well of the heating device. This heat will naturally be taken up by the flask 12 positioned over the well. The flask illustrated is a conical flask but these flasks are sometimes also made spherical and may have other shapes as well.

In any case, a substantially point source of heat is provided which is directed to the lower end of the flask so that even the tiniest amounts of liquid therein are properly heated and the liquid can be distilled down to the very last drop.

The heating device is suitable for any type of microfiasks regardless of the shape or size thereof. Larger flasks are substantially conventional in size and shape and the heating device of the nature referred to its not necessary, although it could be used for larger flasks if so desired. The principal use of the device, however, is connection with the microflasks which might contain only a teaspoon full of liquid to be treated.

FIGURE 3 shows more in detail the arrangement of the heating element and the well. In FIGURE 3 it will be seen that the resistance heating wire 42 is encased in a textile tube 62 and inside the tube is high temperature electrical insulation 64. The heating element is wound about well 38 and is held in the well and convolutions of the heating element are held apart by cord 66 which may be of glass or asbestos fibers or the like.

An insulating sleeve 68 of a refractory fiber surrounds well 38.

It will be understood that this invention is susceptible to modification in order to adapt it to different usages and conditions; and accordingly, it is desired to comprehend such modifications within this invention as may fall within the scope of the appended claims.

I claim:

1. An electric heating device, especially for use with extremely small flasks, which comprises: a cup-like body having a metallic peripheral wall and a metallic bottom wall, a disc-like member of rigid refractory material on top of said body forming a top wall therefor, a central aperture in said top wall, a Well member in said body opening upwardly and having its upper open end extending through the opening in said top wall and flared out to form a seat on which the bottom of a flask can rest, said Well having a radially outwardly projecting flange at the bottom defining a channel with the lower side of said top wall, an electrical resistance heating element wound about said well member in distributed relation along said channel, said electric resistance heating element comprising individual wires encased in refractory textile tubes with high temperature insulation therein, said heating element Wound around said well member in said channel together with a refractory cord of substantial cross section, said cord holding said heating element thereon and spacing at least some of the adjacent convolutions of the heating element from each other to maintain the heating element in distributed relation in said channel, and means extending into said body for supplying electrical energy thereto, and heat insulation material in said body surrounding said well member and said heating element.

2. An electric heating device according to claim 1, which includes a member fixedly mounted on said body and adapted for detachably receiving a support element to support said heating device.

References Cited UNITED STATES PATENTS 1,033,799 7/1912 Harvey 219433 1,203,406 10/1916 Redekcr 219--521 1,295,045 2/ 1919 Lidberg 219433 X 1,581,259 4/1926 Wiechert et a1. 219-521 X 1,762,171 6/1930 Goldsmith 219-436 1,824,585 9/ 1931 Wolcott et a1 2195-2 1 1,872,730 8/1932 Goldfisch 2.19521 2,535,731 12/ 1950 Goodenl'ath 219433 2,767,300 10/1956 De Verter 219-421 2,842,654 7/ 1958 Anderson 219-433 1,649,067 11/ 1927 Karlson 219-436 ANTHONY BARTIS, Prmary Examiner.

US. Cl. X.R. 

